Every date on the calendar carries pieces of the human story, and September 20 is no exception. Across centuries, this day has witnessed exploration, warfare, political change, scientific achievement, entertainment milestones, and moments that influenced popular culture.
From Ferdinand Magellan beginning one of history’s most famous voyages to the Battle of the Sexes between Billie Jean King and Bobby Riggs, September 20 connects dramatically different eras of history.
It is a day that reminds us that history is not simply a collection of dates. It is the continuing story of people challenging boundaries, competing for change, creating new ideas, and leaving their influence on generations that follow.
1519 — Ferdinand Magellan Begins His Historic Expedition
One of the most significant voyages in the history of exploration began on September 20, 1519.
Portuguese navigator Ferdinand Magellan, sailing on behalf of Spain, departed with a fleet on an expedition intended to find a westward route to the Spice Islands.
The journey would become much more important than anyone aboard could have imagined.
Magellan himself would not survive the expedition. He was killed in the Philippines in 1521. However, one of the ships, the Victoria, eventually returned to Spain under the command of Juan Sebastián Elcano in September 1522.
The expedition became the first recorded circumnavigation of the Earth.
The voyage demonstrated in practical terms the enormous scale of the planet and showed that the world’s oceans were interconnected.
Only a small portion of the original crew completed the entire journey.
Today, the Magellan-Elcano expedition remains one of the most remarkable accomplishments of the Age of Exploration.
At the same time, modern discussions of European exploration also recognize its darker consequences. Voyages of exploration helped accelerate European colonial expansion, conquest, exploitation, and dramatic changes for Indigenous populations around the world.
The expedition therefore represents both extraordinary human navigation and the beginning of profound global transformations.
1870 — Rome Is Captured During Italian Unification
September 20, 1870, became an important date in the history of modern Italy.
Italian forces entered Rome after breaking through the city’s defenses at Porta Pia.
The event effectively ended the Papal States as a major territorial political power and helped complete the long process of Italian unification known as the Risorgimento.
Rome was soon incorporated into the Kingdom of Italy and became the nation’s capital the following year.
The relationship between the Italian government and the papacy remained complicated for decades afterward.
The dispute was eventually addressed through the Lateran Treaty of 1929, which established Vatican City as an independent sovereign state.
September 20 therefore represents a major turning point in the creation of modern Italy.
1881 — Chester A. Arthur Becomes President
American politics experienced an unexpected transition on September 20, 1881.
Vice President Chester A. Arthur was sworn in as the 21st president of the United States following the death of President James A. Garfield.
Garfield had been shot by Charles Guiteau on July 2, 1881. He survived for more than two months before dying on September 19.
Arthur’s rise to the presidency surprised many Americans.
Before becoming vice president, he had been associated with New York’s political machine and the patronage system. Critics therefore expected his administration to continue traditional machine politics.
Instead, Arthur surprised some of those critics by supporting civil service reform.
During his administration, the Pendleton Civil Service Reform Act was signed into law in 1883.
The legislation helped establish a federal employment system in which certain government positions were awarded based on competitive examinations rather than simply political loyalty.
Arthur’s presidency became an example of how unexpected circumstances can reshape both political careers and public perceptions.
1946 — The First Cannes Film Festival Begins
September 20, 1946, marked the opening of the first Cannes Film Festival in Cannes, France.
The festival had originally been planned before World War II, but the outbreak of war disrupted those plans.
After the war ended, filmmakers, actors, critics, and representatives from numerous countries gathered on the French Riviera to celebrate international cinema.
The festival eventually became one of the most prestigious film events in the world.
Its highest honor, the Palme d’Or, has become one of cinema’s most respected awards.
Cannes has also played an important cultural role beyond simply presenting awards.
The festival has introduced international audiences to filmmakers and cinematic movements they might otherwise never have encountered.
Independent films, experimental filmmaking, international productions, and emerging directors have all found important audiences through Cannes.
The festival demonstrates how cinema can cross borders and allow stories created in one culture to connect with people living thousands of miles away.
1954 — The First FORTRAN Program Is Successfully Run
September 20 also has an important connection to the history of computing.
During the 1950s, IBM researchers led by John Backus worked on a revolutionary programming language known as FORTRAN, short for Formula Translation.
FORTRAN was designed to make programming scientific and mathematical calculations easier.
Before high-level programming languages became common, programmers frequently had to work much closer to the machine’s underlying instructions.
FORTRAN helped change that.
It allowed scientists, engineers, mathematicians, and programmers to write instructions in a form that was easier for humans to understand while a compiler translated those instructions into machine code.
FORTRAN became enormously influential in scientific computing and helped demonstrate the potential of high-level programming languages.
Remarkably, descendants of FORTRAN continue to be used for certain scientific and engineering applications decades later.
Its development represents one of the important steps toward the software-driven world we live in today.
1973 — Billie Jean King Wins the “Battle of the Sexes”
One of the most famous sporting events of the twentieth century took place on September 20, 1973.
Tennis champion Billie Jean King faced former men’s tennis star Bobby Riggs at the Houston Astrodome in an exhibition match famously promoted as the Battle of the Sexes.
Riggs had publicly claimed that even at his age he could defeat leading female tennis players.
The match became much larger than tennis.
Millions of people watched as King defeated Riggs in straight sets:
6–4, 6–3, 6–3.
King’s victory became an important cultural moment during a period when women were fighting for greater equality in employment, education, athletics, and society.
King had already become an outspoken advocate for equal prize money in professional tennis.
Her victory over Riggs gave that broader conversation an enormous international platform.
The Battle of the Sexes remains one of the clearest examples of a sporting event becoming a cultural event.
The final score mattered, but what the match represented mattered even more.
1977 — Television Audiences Meet Fonzie’s Famous Shark Jump
Popular culture also remembers September 20 because of a television moment that eventually created a phrase still used today.
An episode of the hit television series Happy Days aired in September 1977 featuring Arthur “Fonzie” Fonzarelli, played by Henry Winkler, waterskiing over a shark.
Fonzie was even wearing his famous leather jacket while doing it.
Years later, the scene inspired the expression “jumping the shark.”
The phrase is now commonly used when a television series—or sometimes another creative project—introduces an increasingly unbelievable gimmick in an attempt to maintain excitement or popularity.
Ironically, Happy Days continued successfully for years afterward.
Still, the phrase became permanently embedded in entertainment culture.
Today someone might say a television series “jumped the shark” when they believe it passed its creative peak.
It is an interesting example of how a single television scene can eventually create an expression recognized far beyond the original program.
1984 — The Cosby Show Premieres
September 20, 1984, marked the premiere of The Cosby Show on NBC.
The sitcom centered on the Huxtable family and became one of the highest-rated television programs of the 1980s.
Its portrayal of an affluent Black American family was especially significant in the television landscape of the era.
Cliff Huxtable was portrayed as a physician, while Clair Huxtable was an attorney.
The show helped broaden mainstream television portrayals of Black family life and influenced generations of family sitcoms that followed.
Its cultural legacy has become more complicated because of the later criminal cases and sexual assault allegations involving its star, Bill Cosby.
That complicated history illustrates an important part of studying popular culture: the cultural impact of a work can sometimes become inseparable from later revelations involving the people associated with it.
1985 — Walt Disney World Welcomes Its 200 Millionth Guest
By the mid-1980s, Walt Disney World had become one of the world’s most recognizable vacation destinations.
On September 20, 1985, the Florida resort welcomed its 200 millionth guest.
The milestone demonstrated how dramatically theme parks had grown as a form of American entertainment and tourism.
Disney had transformed the idea of an amusement park into something much larger—a carefully designed environment built around storytelling, characters, architecture, music, technology, hospitality, and immersive experiences.
The influence of Disney’s parks can now be seen throughout the global entertainment and tourism industries.
Theme parks increasingly became destinations where families might spend several days rather than simply visiting for an afternoon.
September 20 and the Evolution of Popular Culture
One fascinating aspect of September 20 is how many different forms of culture intersect on this date.
Cinema appears through the Cannes Film Festival.
Television appears through programs such as Happy Days and The Cosby Show.
Sports and social change intersect through Billie Jean King’s Battle of the Sexes.
Technology appears through the development of programming languages such as FORTRAN.
Exploration appears through Magellan’s expedition.
Politics appears through Italian unification and the unexpected presidency of Chester A. Arthur.
Together, these events demonstrate that culture is constantly being created.
Something that appears to be ordinary entertainment today may become a cultural reference decades later.
A sporting event can influence social attitudes.
A new technology can change how future generations work.
A political event can redefine an entire nation.
And an expedition can permanently change humanity’s understanding of the world.
Notable People Born on September 20
September 20 is also the birthday of several people who left their mark on entertainment, literature, sports, politics, and popular culture.
Upton Sinclair — Born in 1878
American author and social reformer Upton Sinclair became famous for exposing difficult working and living conditions through his writing.
His 1906 novel The Jungle examined the lives of immigrant workers in Chicago’s meatpacking industry.
The book shocked readers with its descriptions of working conditions and food production practices and contributed to public pressure for stronger food safety regulations.
Red Auerbach — Born in 1917
Basketball coach and executive Red Auerbach became one of the most influential figures in NBA history.
He is most closely associated with the Boston Celtics dynasty and helped shape professional basketball through coaching, management, and talent development.
Sophia Loren — Born in 1934
Italian actress Sophia Loren became one of the great international film stars of the twentieth century.
Her career crossed linguistic and cultural boundaries, and she became widely recognized for performances in both Italian and international productions.
Her Academy Award-winning performance in Two Women helped demonstrate that international-language performances could achieve major recognition in Hollywood.
George R. R. Martin — Born in 1948
American author George R. R. Martin is best known for the fantasy series A Song of Ice and Fire.
The books became the foundation for the enormously successful television series Game of Thrones.
Martin’s work helped reshape modern fantasy storytelling through complicated characters, political conflict, moral ambiguity, and unpredictable plot developments.
Why September 20 Matters
The historical events associated with September 20 span more than five centuries.
They include ships crossing unknown oceans, armies entering Rome, an unexpected presidential transition, filmmakers gathering after a devastating world war, programmers creating new ways to communicate with computers, and a female tennis champion stepping onto a court knowing that millions of people viewed her match as something much larger than sports.
These moments seem unrelated at first.
But together they reveal something important about history.
Human civilization continually changes because people explore, compete, invent, challenge traditions, tell stories, and imagine different possibilities.
Sometimes history changes through dramatic political events.
Sometimes it changes through technology.
Sometimes it changes through art.
And sometimes millions of people watch a tennis match that becomes a symbol of an entire social movement.
Final Thoughts
September 20 reminds us that history and culture are deeply connected.
The voyage that began under Ferdinand Magellan helped reshape global exploration. The capture of Rome helped complete Italian unification. Chester A. Arthur entered the White House under tragic circumstances and became associated with civil service reform. Cannes developed into one of cinema’s great international gatherings. Advances in programming helped prepare the way for modern computing.
And in 1973, Billie Jean King walked onto a tennis court and demonstrated how sports can become a stage for something much larger than competition.
History is not only found in textbooks, monuments, or museums.
It lives in the technology we use, the expressions we repeat, the films we watch, the sports we celebrate, and the political institutions that shape our societies.
Every day adds another chapter.
September 20 has already written many of its own.
Which September 20 moment do you think had the greatest impact on history or culture?
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